This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Node.js Backend Developer Sênior based in Brazil. This is an exciting opportunity for a senior backend engineer to work on mission-critical platforms that process and distribute clinical and laboratory data at scale. In this role, you will contribute to the design and evolution of modern distributed systems, helping build secure, reliable, and high-performance services in a highly collaborative environment. You will work with microservices, event-driven architectures, and cloud-native technologies while influencing technical decisions and driving continuous improvements across products and integrations. The position is ideal for professionals who thrive in complex ecosystems, enjoy solving challenging problems, and are passionate about software quality, scalability, and innovation.